Genealogy / Kosko, Nowacka - Looking for relatives originally from Ostrow Mazowieski [3]

I would like to visit Poland, but only if I can find some relatives. Both sides of my family came from Ostrow Mazowieski. My father's name was Kazimierz Kosko (1907) and his parents were Joseph Kosko and Walentyna Nowacka. He had two sisters who remained in Poland. I think that one married a Lewandowski and they had a daughter Asia. My mother's name was Balbina Brejnak (1909). Her parents were Kazimierz Brejnak and Anna Przybylowska. My mother had a brother Henry who also stayed in Poland and I believe had a couple of sons. I would love to find any of my nieces or nephews.